1/*
2 * Driver for Linear Technology LTC2945 I2C Power Monitor
3 *
4 * Copyright (c) 2014 Guenter Roeck
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 */
16
17#include <linux/kernel.h>
18#include <linux/module.h>
19#include <linux/err.h>
20#include <linux/slab.h>
21#include <linux/i2c.h>
22#include <linux/hwmon.h>
23#include <linux/hwmon-sysfs.h>
24#include <linux/jiffies.h>
25#include <linux/regmap.h>
26
27/* chip registers */
28#define LTC2945_CONTROL 0x00
29#define LTC2945_ALERT 0x01
30#define LTC2945_STATUS 0x02
31#define LTC2945_FAULT 0x03
32#define LTC2945_POWER_H 0x05
33#define LTC2945_MAX_POWER_H 0x08
34#define LTC2945_MIN_POWER_H 0x0b
35#define LTC2945_MAX_POWER_THRES_H 0x0e
36#define LTC2945_MIN_POWER_THRES_H 0x11
37#define LTC2945_SENSE_H 0x14
38#define LTC2945_MAX_SENSE_H 0x16
39#define LTC2945_MIN_SENSE_H 0x18
40#define LTC2945_MAX_SENSE_THRES_H 0x1a
41#define LTC2945_MIN_SENSE_THRES_H 0x1c
42#define LTC2945_VIN_H 0x1e
43#define LTC2945_MAX_VIN_H 0x20
44#define LTC2945_MIN_VIN_H 0x22
45#define LTC2945_MAX_VIN_THRES_H 0x24
46#define LTC2945_MIN_VIN_THRES_H 0x26
47#define LTC2945_ADIN_H 0x28
48#define LTC2945_MAX_ADIN_H 0x2a
49#define LTC2945_MIN_ADIN_H 0x2c
50#define LTC2945_MAX_ADIN_THRES_H 0x2e
51#define LTC2945_MIN_ADIN_THRES_H 0x30
52#define LTC2945_MIN_ADIN_THRES_L 0x31
53
54/* Fault register bits */
55
56#define FAULT_ADIN_UV (1 << 0)
57#define FAULT_ADIN_OV (1 << 1)
58#define FAULT_VIN_UV (1 << 2)
59#define FAULT_VIN_OV (1 << 3)
60#define FAULT_SENSE_UV (1 << 4)
61#define FAULT_SENSE_OV (1 << 5)
62#define FAULT_POWER_UV (1 << 6)
63#define FAULT_POWER_OV (1 << 7)
64
65/* Control register bits */
66
67#define CONTROL_MULT_SELECT (1 << 0)
68#define CONTROL_TEST_MODE (1 << 4)
69
70static inline bool is_power_reg(u8 reg)
71{
72 return reg < LTC2945_SENSE_H;
73}
74
75/* Return the value from the given register in uW, mV, or mA */
76static long long ltc2945_reg_to_val(struct device *dev, u8 reg)
77{
78 struct regmap *regmap = dev_get_drvdata(dev);
79 unsigned int control;
80 u8 buf[3];
81 long long val;
82 int ret;
83
84 ret = regmap_bulk_read(regmap, reg, buf,
85 is_power_reg(reg) ? 3 : 2);
86 if (ret < 0)
87 return ret;
88
89 if (is_power_reg(reg)) {
90 /* power */
91 val = (buf[0] << 16) + (buf[1] << 8) + buf[2];
92 } else {
93 /* current, voltage */
94 val = (buf[0] << 4) + (buf[1] >> 4);
95 }
96
97 switch (reg) {
98 case LTC2945_POWER_H:
99 case LTC2945_MAX_POWER_H:
100 case LTC2945_MIN_POWER_H:
101 case LTC2945_MAX_POWER_THRES_H:
102 case LTC2945_MIN_POWER_THRES_H:
103 /*
104 * Convert to uW by assuming current is measured with
105 * an 1mOhm sense resistor, similar to current
106 * measurements.
107 * Control register bit 0 selects if voltage at SENSE+/VDD
108 * or voltage at ADIN is used to measure power.
109 */
110 ret = regmap_read(regmap, LTC2945_CONTROL, &control);
111 if (ret < 0)
112 return ret;
113 if (control & CONTROL_MULT_SELECT) {
114 /* 25 mV * 25 uV = 0.625 uV resolution. */
115 val *= 625LL;
116 } else {
117 /* 0.5 mV * 25 uV = 0.0125 uV resolution. */
118 val = (val * 25LL) >> 1;
119 }
120 break;
121 case LTC2945_VIN_H:
122 case LTC2945_MAX_VIN_H:
123 case LTC2945_MIN_VIN_H:
124 case LTC2945_MAX_VIN_THRES_H:
125 case LTC2945_MIN_VIN_THRES_H:
126 /* 25 mV resolution. Convert to mV. */
127 val *= 25;
128 break;
129 case LTC2945_ADIN_H:
130 case LTC2945_MAX_ADIN_H:
131 case LTC2945_MIN_ADIN_THRES_H:
132 case LTC2945_MAX_ADIN_THRES_H:
133 case LTC2945_MIN_ADIN_H:
134 /* 0.5mV resolution. Convert to mV. */
135 val = val >> 1;
136 break;
137 case LTC2945_SENSE_H:
138 case LTC2945_MAX_SENSE_H:
139 case LTC2945_MIN_SENSE_H:
140 case LTC2945_MAX_SENSE_THRES_H:
141 case LTC2945_MIN_SENSE_THRES_H:
142 /*
143 * 25 uV resolution. Convert to current as measured with
144 * an 1 mOhm sense resistor, in mA. If a different sense
145 * resistor is installed, calculate the actual current by
146 * dividing the reported current by the sense resistor value
147 * in mOhm.
148 */
149 val *= 25;
150 break;
151 default:
152 return -EINVAL;
153 }
154 return val;
155}
156
157static int ltc2945_val_to_reg(struct device *dev, u8 reg,
158 unsigned long val)
159{
160 struct regmap *regmap = dev_get_drvdata(dev);
161 unsigned int control;
162 int ret;
163
164 switch (reg) {
165 case LTC2945_POWER_H:
166 case LTC2945_MAX_POWER_H:
167 case LTC2945_MIN_POWER_H:
168 case LTC2945_MAX_POWER_THRES_H:
169 case LTC2945_MIN_POWER_THRES_H:
170 /*
171 * Convert to register value by assuming current is measured
172 * with an 1mOhm sense resistor, similar to current
173 * measurements.
174 * Control register bit 0 selects if voltage at SENSE+/VDD
175 * or voltage at ADIN is used to measure power, which in turn
176 * determines register calculations.
177 */
178 ret = regmap_read(regmap, LTC2945_CONTROL, &control);
179 if (ret < 0)
180 return ret;
181 if (control & CONTROL_MULT_SELECT) {
182 /* 25 mV * 25 uV = 0.625 uV resolution. */
183 val = DIV_ROUND_CLOSEST(val, 625);
184 } else {
185 /*
186 * 0.5 mV * 25 uV = 0.0125 uV resolution.
187 * Divide first to avoid overflow;
188 * accept loss of accuracy.
189 */
190 val = DIV_ROUND_CLOSEST(val, 25) * 2;
191 }
192 break;
193 case LTC2945_VIN_H:
194 case LTC2945_MAX_VIN_H:
195 case LTC2945_MIN_VIN_H:
196 case LTC2945_MAX_VIN_THRES_H:
197 case LTC2945_MIN_VIN_THRES_H:
198 /* 25 mV resolution. */
199 val /= 25;
200 break;
201 case LTC2945_ADIN_H:
202 case LTC2945_MAX_ADIN_H:
203 case LTC2945_MIN_ADIN_THRES_H:
204 case LTC2945_MAX_ADIN_THRES_H:
205 case LTC2945_MIN_ADIN_H:
206 /* 0.5mV resolution. */
207 val *= 2;
208 break;
209 case LTC2945_SENSE_H:
210 case LTC2945_MAX_SENSE_H:
211 case LTC2945_MIN_SENSE_H:
212 case LTC2945_MAX_SENSE_THRES_H:
213 case LTC2945_MIN_SENSE_THRES_H:
214 /*
215 * 25 uV resolution. Convert to current as measured with
216 * an 1 mOhm sense resistor, in mA. If a different sense
217 * resistor is installed, calculate the actual current by
218 * dividing the reported current by the sense resistor value
219 * in mOhm.
220 */
221 val = DIV_ROUND_CLOSEST(val, 25);
222 break;
223 default:
224 return -EINVAL;
225 }
226 return val;
227}
228
229static ssize_t ltc2945_value_show(struct device *dev,
230 struct device_attribute *da, char *buf)
231{
232 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
233 long long value;
234
235 value = ltc2945_reg_to_val(dev, attr->index);
236 if (value < 0)
237 return value;
238 return snprintf(buf, PAGE_SIZE, "%lld\n", value);
239}
240
241static ssize_t ltc2945_value_store(struct device *dev,
242 struct device_attribute *da,
243 const char *buf, size_t count)
244{
245 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
246 struct regmap *regmap = dev_get_drvdata(dev);
247 u8 reg = attr->index;
248 unsigned long val;
249 u8 regbuf[3];
250 int num_regs;
251 int regval;
252 int ret;
253
254 ret = kstrtoul(buf, 10, &val);
255 if (ret)
256 return ret;
257
258 /* convert to register value, then clamp and write result */
259 regval = ltc2945_val_to_reg(dev, reg, val);
260 if (is_power_reg(reg)) {
261 regval = clamp_val(regval, 0, 0xffffff);
262 regbuf[0] = regval >> 16;
263 regbuf[1] = (regval >> 8) & 0xff;
264 regbuf[2] = regval;
265 num_regs = 3;
266 } else {
267 regval = clamp_val(regval, 0, 0xfff) << 4;
268 regbuf[0] = regval >> 8;
269 regbuf[1] = regval & 0xff;
270 num_regs = 2;
271 }
272 ret = regmap_bulk_write(regmap, reg, regbuf, num_regs);
273 return ret < 0 ? ret : count;
274}
275
276static ssize_t ltc2945_history_store(struct device *dev,
277 struct device_attribute *da,
278 const char *buf, size_t count)
279{
280 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
281 struct regmap *regmap = dev_get_drvdata(dev);
282 u8 reg = attr->index;
283 int num_regs = is_power_reg(reg) ? 3 : 2;
284 u8 buf_min[3] = { 0xff, 0xff, 0xff };
285 u8 buf_max[3] = { 0, 0, 0 };
286 unsigned long val;
287 int ret;
288
289 ret = kstrtoul(buf, 10, &val);
290 if (ret)
291 return ret;
292 if (val != 1)
293 return -EINVAL;
294
295 ret = regmap_update_bits(regmap, LTC2945_CONTROL, CONTROL_TEST_MODE,
296 CONTROL_TEST_MODE);
297
298 /* Reset minimum */
299 ret = regmap_bulk_write(regmap, reg, buf_min, num_regs);
300 if (ret)
301 return ret;
302
303 switch (reg) {
304 case LTC2945_MIN_POWER_H:
305 reg = LTC2945_MAX_POWER_H;
306 break;
307 case LTC2945_MIN_SENSE_H:
308 reg = LTC2945_MAX_SENSE_H;
309 break;
310 case LTC2945_MIN_VIN_H:
311 reg = LTC2945_MAX_VIN_H;
312 break;
313 case LTC2945_MIN_ADIN_H:
314 reg = LTC2945_MAX_ADIN_H;
315 break;
316 default:
317 WARN_ONCE(1, "Bad register: 0x%x\n", reg);
318 return -EINVAL;
319 }
320 /* Reset maximum */
321 ret = regmap_bulk_write(regmap, reg, buf_max, num_regs);
322
323 /* Try resetting test mode even if there was an error */
324 regmap_update_bits(regmap, LTC2945_CONTROL, CONTROL_TEST_MODE, 0);
325
326 return ret ? : count;
327}
328
329static ssize_t ltc2945_bool_show(struct device *dev,
330 struct device_attribute *da, char *buf)
331{
332 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
333 struct regmap *regmap = dev_get_drvdata(dev);
334 unsigned int fault;
335 int ret;
336
337 ret = regmap_read(regmap, LTC2945_FAULT, &fault);
338 if (ret < 0)
339 return ret;
340
341 fault &= attr->index;
342 if (fault) /* Clear reported faults in chip register */
343 regmap_update_bits(regmap, LTC2945_FAULT, attr->index, 0);
344
345 return snprintf(buf, PAGE_SIZE, "%d\n", !!fault);
346}
347
348/* Input voltages */
349
350static SENSOR_DEVICE_ATTR_RO(in1_input, ltc2945_value, LTC2945_VIN_H);
351static SENSOR_DEVICE_ATTR_RW(in1_min, ltc2945_value, LTC2945_MIN_VIN_THRES_H);
352static SENSOR_DEVICE_ATTR_RW(in1_max, ltc2945_value, LTC2945_MAX_VIN_THRES_H);
353static SENSOR_DEVICE_ATTR_RO(in1_lowest, ltc2945_value, LTC2945_MIN_VIN_H);
354static SENSOR_DEVICE_ATTR_RO(in1_highest, ltc2945_value, LTC2945_MAX_VIN_H);
355static SENSOR_DEVICE_ATTR_WO(in1_reset_history, ltc2945_history,
356 LTC2945_MIN_VIN_H);
357
358static SENSOR_DEVICE_ATTR_RO(in2_input, ltc2945_value, LTC2945_ADIN_H);
359static SENSOR_DEVICE_ATTR_RW(in2_min, ltc2945_value, LTC2945_MIN_ADIN_THRES_H);
360static SENSOR_DEVICE_ATTR_RW(in2_max, ltc2945_value, LTC2945_MAX_ADIN_THRES_H);
361static SENSOR_DEVICE_ATTR_RO(in2_lowest, ltc2945_value, LTC2945_MIN_ADIN_H);
362static SENSOR_DEVICE_ATTR_RO(in2_highest, ltc2945_value, LTC2945_MAX_ADIN_H);
363static SENSOR_DEVICE_ATTR_WO(in2_reset_history, ltc2945_history,
364 LTC2945_MIN_ADIN_H);
365
366/* Voltage alarms */
367
368static SENSOR_DEVICE_ATTR_RO(in1_min_alarm, ltc2945_bool, FAULT_VIN_UV);
369static SENSOR_DEVICE_ATTR_RO(in1_max_alarm, ltc2945_bool, FAULT_VIN_OV);
370static SENSOR_DEVICE_ATTR_RO(in2_min_alarm, ltc2945_bool, FAULT_ADIN_UV);
371static SENSOR_DEVICE_ATTR_RO(in2_max_alarm, ltc2945_bool, FAULT_ADIN_OV);
372
373/* Currents (via sense resistor) */
374
375static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc2945_value, LTC2945_SENSE_H);
376static SENSOR_DEVICE_ATTR_RW(curr1_min, ltc2945_value,
377 LTC2945_MIN_SENSE_THRES_H);
378static SENSOR_DEVICE_ATTR_RW(curr1_max, ltc2945_value,
379 LTC2945_MAX_SENSE_THRES_H);
380static SENSOR_DEVICE_ATTR_RO(curr1_lowest, ltc2945_value, LTC2945_MIN_SENSE_H);
381static SENSOR_DEVICE_ATTR_RO(curr1_highest, ltc2945_value,
382 LTC2945_MAX_SENSE_H);
383static SENSOR_DEVICE_ATTR_WO(curr1_reset_history, ltc2945_history,
384 LTC2945_MIN_SENSE_H);
385
386/* Current alarms */
387
388static SENSOR_DEVICE_ATTR_RO(curr1_min_alarm, ltc2945_bool, FAULT_SENSE_UV);
389static SENSOR_DEVICE_ATTR_RO(curr1_max_alarm, ltc2945_bool, FAULT_SENSE_OV);
390
391/* Power */
392
393static SENSOR_DEVICE_ATTR_RO(power1_input, ltc2945_value, LTC2945_POWER_H);
394static SENSOR_DEVICE_ATTR_RW(power1_min, ltc2945_value,
395 LTC2945_MIN_POWER_THRES_H);
396static SENSOR_DEVICE_ATTR_RW(power1_max, ltc2945_value,
397 LTC2945_MAX_POWER_THRES_H);
398static SENSOR_DEVICE_ATTR_RO(power1_input_lowest, ltc2945_value,
399 LTC2945_MIN_POWER_H);
400static SENSOR_DEVICE_ATTR_RO(power1_input_highest, ltc2945_value,
401 LTC2945_MAX_POWER_H);
402static SENSOR_DEVICE_ATTR_WO(power1_reset_history, ltc2945_history,
403 LTC2945_MIN_POWER_H);
404
405/* Power alarms */
406
407static SENSOR_DEVICE_ATTR_RO(power1_min_alarm, ltc2945_bool, FAULT_POWER_UV);
408static SENSOR_DEVICE_ATTR_RO(power1_max_alarm, ltc2945_bool, FAULT_POWER_OV);
409
410static struct attribute *ltc2945_attrs[] = {
411 &sensor_dev_attr_in1_input.dev_attr.attr,
412 &sensor_dev_attr_in1_min.dev_attr.attr,
413 &sensor_dev_attr_in1_max.dev_attr.attr,
414 &sensor_dev_attr_in1_lowest.dev_attr.attr,
415 &sensor_dev_attr_in1_highest.dev_attr.attr,
416 &sensor_dev_attr_in1_reset_history.dev_attr.attr,
417 &sensor_dev_attr_in1_min_alarm.dev_attr.attr,
418 &sensor_dev_attr_in1_max_alarm.dev_attr.attr,
419
420 &sensor_dev_attr_in2_input.dev_attr.attr,
421 &sensor_dev_attr_in2_min.dev_attr.attr,
422 &sensor_dev_attr_in2_max.dev_attr.attr,
423 &sensor_dev_attr_in2_lowest.dev_attr.attr,
424 &sensor_dev_attr_in2_highest.dev_attr.attr,
425 &sensor_dev_attr_in2_reset_history.dev_attr.attr,
426 &sensor_dev_attr_in2_min_alarm.dev_attr.attr,
427 &sensor_dev_attr_in2_max_alarm.dev_attr.attr,
428
429 &sensor_dev_attr_curr1_input.dev_attr.attr,
430 &sensor_dev_attr_curr1_min.dev_attr.attr,
431 &sensor_dev_attr_curr1_max.dev_attr.attr,
432 &sensor_dev_attr_curr1_lowest.dev_attr.attr,
433 &sensor_dev_attr_curr1_highest.dev_attr.attr,
434 &sensor_dev_attr_curr1_reset_history.dev_attr.attr,
435 &sensor_dev_attr_curr1_min_alarm.dev_attr.attr,
436 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
437
438 &sensor_dev_attr_power1_input.dev_attr.attr,
439 &sensor_dev_attr_power1_min.dev_attr.attr,
440 &sensor_dev_attr_power1_max.dev_attr.attr,
441 &sensor_dev_attr_power1_input_lowest.dev_attr.attr,
442 &sensor_dev_attr_power1_input_highest.dev_attr.attr,
443 &sensor_dev_attr_power1_reset_history.dev_attr.attr,
444 &sensor_dev_attr_power1_min_alarm.dev_attr.attr,
445 &sensor_dev_attr_power1_max_alarm.dev_attr.attr,
446
447 NULL,
448};
449ATTRIBUTE_GROUPS(ltc2945);
450
451static const struct regmap_config ltc2945_regmap_config = {
452 .reg_bits = 8,
453 .val_bits = 8,
454 .max_register = LTC2945_MIN_ADIN_THRES_L,
455};
456
457static int ltc2945_probe(struct i2c_client *client,
458 const struct i2c_device_id *id)
459{
460 struct device *dev = &client->dev;
461 struct device *hwmon_dev;
462 struct regmap *regmap;
463
464 regmap = devm_regmap_init_i2c(client, &ltc2945_regmap_config);
465 if (IS_ERR(regmap)) {
466 dev_err(dev, "failed to allocate register map\n");
467 return PTR_ERR(regmap);
468 }
469
470 /* Clear faults */
471 regmap_write(regmap, LTC2945_FAULT, 0x00);
472
473 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
474 regmap,
475 ltc2945_groups);
476 return PTR_ERR_OR_ZERO(hwmon_dev);
477}
478
479static const struct i2c_device_id ltc2945_id[] = {
480 {"ltc2945", 0},
481 { }
482};
483
484MODULE_DEVICE_TABLE(i2c, ltc2945_id);
485
486static struct i2c_driver ltc2945_driver = {
487 .driver = {
488 .name = "ltc2945",
489 },
490 .probe = ltc2945_probe,
491 .id_table = ltc2945_id,
492};
493
494module_i2c_driver(ltc2945_driver);
495
496MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
497MODULE_DESCRIPTION("LTC2945 driver");
498MODULE_LICENSE("GPL");
499